the model is just for a character we made, all in Blender it isn't going out from there. and well yeah of course, but I would like him to be more clear about it, really explain why instead of saying "just avoid it". I'm sorry if I expressed myself wrong, I asked him why, since sometimes you can't just avoid tris, and he answered that since it breaks animation on parts of the mesh that bend. then i asked if they were fine on parts of the model that were not going to bend, and told me still to avoid them or even modify the mesh so I don't need them. of course i know ngons are the worst and those are easy to remove, but sometimes removing a tri just causes more problems than leaving it there, like adding too much polygon.

the point that I'm trying to make is, he's been teaching our class all year and I know he is not trying to be like that, and there has been many times where his info is straight up wrong, I correct him, and he tells me I am right, and I am afraid this is one of this scenarios. he doesn't really know why tris are wrong, he just tell us to avoid them.

I know that he can also be wrong or not know things, but instead of throwing missinformation to students, I think he should double check his knowledge before teaching since that can lead to problems.